Typical power converter systems use electrolytic or foil capacitors to realize DC link and/or snubber circuits. For example, the DC link in an AC-DC-AC converter is normally equipped with an electrolytic capacitor which provides decoupling between a rectifier and an inverter. Snubbers are circuits which are placed across power semiconductor devices for protection and to improve performance. A snubber used in the case of IGBT (insulated gate bipolar) switches usually has no resistors or diodes. Instead the snubber is merely used to lower the effective inductance of the system by taking the amount of energy stored in the stray inductors between a DC-link-capacitor bank and itself. As a consequence, the inductance between the snubbers and modules should be as low as possible which means that the snubbers should be connected in a low inductance way as close as possible to the semiconductor module. In each case, the capacitors used in power converter systems are conventionally packaged in cylindrical aluminum tubes (electrolytic capacitor) or in cuboid plastic or metal boxes.
Screws or solder terminals are typically used to connect electrolytic and foil capacitors to a metal sheet or busbar of a power module. In some cases the snubber capacitors are directly mounted to the power terminals of the power module. However conventional capacitor types and connection techniques have several disadvantages. For example, forming screw-based connections is relatively time consuming in that each capacitor is individually screwed down to a terminal on a metal sheet or busbar. Solder-based connections have well known reliability issues. In addition to the shortcomings associated with conventional capacitor attach techniques, terminal constructions typically used in power modules concentrate current flow to a relatively narrow path and therefore increase inductance. High inductance is undesirable for many types of power system applications. Also, heat transfer is not optimal with conventional capacitor types and connection techniques due to the lack of a thermally efficient capacitor-cooler interface.